Polarized Gratings Phase Reconfigurable Metasurface and Its Application in Reconfigurable Transmitarray Antennas

This paper introduces a phase reconfigurable metasurface based on polarized grating and its application in the two-dimension (2-D) beam scanning reconfigurable transmission antenna (TA). The polarized grating structure is ingeniously designed to work as not only the polarization rotator (PR), but also the direct-current (DC) feeding line, which is due to its prominent high transmission efficiency and low profile. This integrated design avoids the high difficulty of fabrication and expensive cost of the extra designed feeding network. The proposed unit cell consists of two-layer orthogonally oriented gratings as top and bottom layer, and the middle layer is designed with a square ring and two arrows. The 1-bit reconfigurable phase performance is realized by controlling the ON or OFF state of two positive-intrinsic-negative (PIN) diodes arranged in the middle layer. A metal via hole is designed to connect the middle layer and the bottom gratings. The simulation results show the low insertion loss of 0.2 dB with two transmission poles and transmission zeros exhibit high passband flatness and frequency selectivity for two phase states. Then the reconfigurable TA consist of (Formula presented.) units which is simulated, analyzed and a prototype is fabricated and measured. The real-time beam scanning performance shows high accuracy and the scanning angles reach (Formula presented.) at (Formula presented.) - and (Formula presented.) -plane with maximum insertion loss of 2.8 dB. The gain of the TA is 18.5 dBi at 10.5 GHz with an aperture efficiency of 22%. The tight agreement between measurement and simulation validates the proposed feeding design and the reconfigurable TA. The proposed feeding design of polarized grating structure with the competitive advantages of low loss, low cost and simple structure, which enables itself one of the design methods of 1-bit reconfigurable TA with relatively high gain and aperture efficiency.